This invention relates to assembly apparatuses for use in an assembly process for magnetic tape cartridges or the like that may flexibly conform to change in production volume and specifications, in which manual operations and operations using an assembly robot are combined. The present invention relates particularly to an assembly apparatus that may easily conform to increase in production volume and change in specifications of parts, and exhibits high production efficiency.
Generally, a product manufactured and sold is subject to change in production volume required in accordance with sales volume of the product. Moreover, change in specifications frequently taking place at the outset of launching a new product would entail changes in shape or the like of parts of the product at times. In this respect, a manual assembly operation is advantageous in adjustability for production volume by means of manpower relocation, and in high conformability to change in specifications. However, on the other hand, such a manual assembly operation is disadvantageously subject to human errors such as an inadvertent skip of some part to be mounted, which would produce deterioration in quality of the product. In contrast, a fully automated assembly apparatus using an assembly robot together with a part-supplying device or a part-supplying tray may advantageously serve to increase production volume, but entails enormous cost of equipment, and requires arrangement of a particular part-supplying device and part-supplying tray dedicated to each part.
Accordingly, once such a particular part-supplying device and part-supplying tray dedicated to each part are arranged in the assembly apparatus, when the part-supplying device and part-supplying tray need be replaced upon change in specifications of parts derived from new product release or the like, several months should be required to design and produce a new part-supplying device and part-supplying tray that conforms to the specifications. Moreover, parts of various specifications may be required mounting in the same location of the same type of products in response to a request from consumers or customers. In such a case, the part-supplying device and the like dedicated to each part, once equipped, would be very difficult to change in conformity to the requirements.
The inventor of the present invention has created an assembly apparatus in which an accurate and fast assembly operation using an assembly robot is combined with a manual operation having high conformability to change in specifications. This assembly apparatus includes a part-supplying station that supplies parts to a predetermined conveyor pallet through a manual operation, and a part-assembling station that assembles the parts provided in the conveyor pallet using an assembly robot. In this assembly apparatus, the parts are placed in the conveyor pallet and conveyed from the part-supplying station to the part-assembling station. The thus-constructed assembly apparatus may easily accommodate change in specifications of the parts only by a partial change in the conveyor pallet, and may prevent defective assembly due to human errors in that the assembly robot takes the parts out of the conveyor pallet and performs an assembly operation.
However, in the assembly apparatus in which a manual part-supplying operation and an assembly operation performed by the assembly robot are combined, the conveyor pallets are conveyed to the assembly robot in the following manner. First, a conveyor pallet in which parts are put is conveyed to a work area where the assembly robot performs an assembly operation. At this stage, the conveyor pallet need accurately stop at the work area so that the assembly robot may not fail to pick up the parts. For that reason, the conveyor pallet is brought into contact with a stopper pin that projects from below a conveyor means provided ahead of the conveyor pallet, for the purpose of provisional positioning of the conveyor pallet. Thereafter, two pins rise from directly below the conveyor pallet, and get fitted into predetermined holes formed on a bottom of the conveyor pallet, so that the conveyor pallet may be accurately positioned.
When the assembly robot finishes assembling parts taken out of the conveyor pallet as necessary, the stopper pin and two pins lower so as to allow the conveyor pallet to move, and the conveyor pallet is conveyed out from the work area. After the conveyor pallet is conveyed out in its entirety from the work area, the above stopper pin rises again to stop a subsequently conveyed conveyor pallet.
In a conventional arrangement as described above, a subsequent conveyor pallet is not conveyed in until a previous conveyor pallet including finished parts is conveyed out in its entirety from the work area. This would disadvantageously generate some idle time for the assembly robot to have no parts to be assembled, and lower a net serviceability ratio of the assembly robot. Such disadvantage would be made more conspicuous, as an operation speed (or line tact) becomes faster. For example, the idle time for three seconds does not matter when the operation speed is 20 seconds/unit; however, if the operation speed were made faster to seven seconds or so with increased number of the assembly robots, the idle time for three seconds would largely affect the production efficiency.
Moreover, the manual operation of supplying parts be conveyed to the assembly robot as in the above-discussed assembly apparatus would possibly entail human errors such as misorientaton of the parts. Therefore, uncorrected mounting of the misoriented parts by the assembly robot would produce a defective product, or difficulty in mounting the misoriented parts would suspend the operation of the assembly apparatus, or like troubles would be encountered. In view of these circumstances, an assembly apparatus that may securely perform an assembly operation even if the parts conveyed to the assembly robot is misoriented has been in demand.
Further, some products among those assembled using the above assembly apparatus would be required to change some components in accordance with their purposes or the like. For example, the magnetic tape cartridge includes a dedicated write-protect type, a data recordable type, a cleaning-use type, or the like, each having a safety lug in varying shapes attached thereto. In order to assemble the magnetic tape cartridges of various types as described above in one and the same assembly apparatus, different safety lugs are manually placed on the conveyor pallet according to the specifications of the target magnetic tape cartridge to be assembled. However, such a manual part-supplying operation might possibly cause a wrong part to be placed on the conveyor pallet due to human errors. Otherwise, even if the part placed were not a wrong part, the part would likely be placed in a position deviated from a predetermined position on the conveyor pallet. Further, even if the manual operation were appropriately performed, the number of the supplied parts might occasionally be different from a predetermined number. In these situations, the conventional assembly apparatus would disadvantageously produce an erroneously assembled product.
Further, in the assembly apparatus as described above in which a manual operation and an operation using an assembly robot are combined, increase in production volume may be achieved by increasing the manpower and the number of robots, and operations may be divided so that operation steps one unit of the assembly robot performs may be reduced. For example, if an arrangement in which one unit of the assembly robot performs nine assembly operations is changed into another arrangement in which three units of the assembly robots perform the same assembly operations, then these nine operations are divided so that each assembly robot may perform three assembly operations. In this arrangement, one assembly robot would perform the operations for a shorter time period, and thus the operation speed could be made faster. On the other hand, the relative time required to convey the conveyor pallet would increase. Consequently, the assembly robot could not pick up parts to be assembled from the conveyor pallet during conveyance of the conveyor pallet, with the result that a net serviceability ratio of the assembly robot would decrease; disadvantageously, the production efficiency could not be raised in proportion to the investment in equipment.
In the above assembly apparatus in which a manual operation and an operation using an assembly robot are combined, when the assembly robot fails to hold a part, or fails to mount a part, or otherwise, the following two measures are taken.
The first approach is to eliminate an abnormal work from a line of the assembly apparatus upon detection of the abnormal work, and keep the assembly apparatus performing the assembly operation without suspension. FIG. 16A depicts an operation flow of this process. It is understood that the assembly robot performing the assembly operation follows the assembly steps 1, 2, . . . , in sequence. If the assembly robot fails to assemble a work during the assembly step 2, the abnormal work is eliminated out of the system when the abnormal work is detected, and discarded or reused, while the assembly apparatus continues assembly operation without suspension. This approach never stops the assembly apparatus, and thus may advantageously make the serviceability ratio higher. On the other hand, the work that has failed to be assembled need be discarded or reassembled manually into a product. If the work is discarded, the yields of the product are reduced, and the loss in costs of the parts is not negligible especially in such an expensive product as a magnetic tape cartridge for use with a computer. If the work is manually reassembled, defect during the assembly operation is likely to occur due to human errors, so that one of the advantageous features of the assembly apparatus as described above would be lost.
The second approach is to stop the assembly apparatus immediately upon detection of the abnormal work, manually reassemble the work failed to be assembled by the assembly robot by performing the suspended step, and restart the assembly operation from a step subsequent to the suspended step. FIG. 16B depicts an operation flow of this process. For example, if the assembly robot fails to assemble a work during the assembly step 2, the assembly apparatus is suspended immediately when the abnormal work is detected. Then, the work is manually amended by properly performing the failed assembly step 2, the amended work is placed in the next assembly step 3, and the assembly apparatus is restarted. This approach may cause the yields of the product to become higher, but could possibly cause a defect in an assembled work due to human errors entailed by manual assembly operations, thus disadvantageously lowering quality of the product.
In view of the aforementioned disadvantages of various kinds, there are provided a variety of embodiments of the present invention. It is an exemplified first object of the present invention to provide an assembly apparatus that may easily conform to increase in production volume and change in specifications of parts, and exhibits high production efficiency.
An exemplified second object of the present invention is to provide an assembly apparatus that may securely perform an assembly operation by allowing an assembly robot to mount a part even if the part conveyed to the assembly robot is in a reverse orientation.
An exemplified third object of the present invention is to provide an assembly apparatus that may prevent a wrong part from being mounted.
An exemplified fourth object of the present invention is to provide an assembly apparatus in which a manual operation and an operation using an assembly robot are combined, which assembly apparatus may serve to raise production efficiency and to make a mass production possible, while saving the investment in equipment.
An exemplified fifth object of the present invention is to provide an abnormal condition handling process in an assembly apparatus in which a manual operation and an operation using an assembly robot are combined, which abnormal condition handling process may keep the yields of the product sufficiently at an adequate level, while keeping the quality of the product at an adequate level.
In order to achieve the above object, there is provided an assembly apparatus comprising a part-supplying station in which parts are supplied to a predetermined conveyor pallet through a manual operation, a part-assembling station in which the parts in the conveyor pallet are assembled through an operation using an assembly robot, and a conveyor means that conveys the conveyor pallet from the part-supplying station to the part-assembling station. In the assembly apparatus, after the assembly robot finishes assembling parts in one conveyor pallet in a work area of the assembly robot, the conveyor means conveys out the one conveyor pallet from the work area, and conveys another conveyor pallet subsequent to the one conveyor pallet into the work area at the same time.
According to the above embodiment of the present invention, conveyance of a conveyor pallet including assembled parts from the work area of the assembly robot may coincide with conveyance of the next conveyor pallet including parts to be assembled into the work area. To be more specific, the subsequent conveyor pallet immediately follows the conveyor pallet including the assembled parts, and thus, the work area would never become vacant as a result of a switching operation for the conveyor pallets, so that the assembly robot may keep operating without idle time.
An assembly apparatus as a second embodiment of the present invention includes an assembly robot that assembles parts conveyed via a conveyor means, the assembly robot being configured to perform an assembly operation, when one of the conveyed parts is placed in a reverse orientation, by correcting the reverse orientation of the part based upon a signal indicating detection of the reverse orientation of the part.
According to the second embodiment of the present invention, if a part conveyed to the assembly robot is in a reverse orientation, the assembly robot corrects the reverse orientation of the part based upon the signal indicating detection of the reverse orientation, and completes the assembly operation. This would serve to prevent the product from getting defective. Moreover, when the parts are supplied through a manual operation, an operator is allowed to supply a part in a reverse orientation, and therefore a burden on the operator is alleviated.
Further provided as a third embodiment of the present invention is an assembly apparatus that assembles parts using an assembly robot, in which the assembly robot includes a gripper portion that holds each part to be assembled, a dimensions measuring means that measures dimensions of the part held by the gripper portion, and a part-identifying means that determines whether the part is a target part to be mounted, based upon the dimensions of the part measured by the dimensions measuring means.
The above assembly apparatus according to the third embodiment of the present invention is for example such that an assembly robot holds and assembles the parts supplied on the conveyor pallet, using the gripper portion of the assembly robot. In this assembly apparatus, dimensions of the part held by the gripper portion are measured in the dimensions measuring means, and it is determined in the part-identifying means whether the part held by the gripper portion is a target part to be assembled, based upon the dimensions measured in the dimensions measuring means. If it is determined that the part held by the gripper portion is different from the target part to be assembled, then for example the assembly operation is suspended, or a warning message is issued, so that defective assembly of the parts may be prevented. Therefore, even in case where products of multiple kinds each containing parts different in size and/or in shape are assembled, particularly in cases such as where parts are manually supplied onto the conveyor pallet, assembly of a wrong part that is likely to occur because the wrong part is supplied onto the conveyor pallet or because a part is erroneously supplied into a position different from a predetermined position on the conveyor pallet may be prevented.
For instance, in an assembly apparatus including a part-supplying station, a part-assembling station, and a conveyor means such as a roller conveyor through which the part-supplying station and the part-assembling station are connected, configured to convey a conveyor pallet via the conveyor means, to supply parts onto the conveyor pallet through a manual operation in the part-supplying station, and to assemble the parts supplied onto the conveyor pallet through an operation using an assembly robot in the part-assembling station, provision of the above dimensions measuring means and the part-identifying means would serve to flexibly conform to change in kind of the product to be assembled, and to prevent erroneous assembly of parts derived from erroneous supply of parts due to human errors and mistakes in position of the supplied parts.
An assembly apparatus as a fourth embodiment of the present invention includes a part-supplying station in which parts are supplied to a predetermined conveyor pallet through a manual operation, a part-assembling station in which the parts in the conveyor pallet are assembled through an operation using an assembly robot, and a conveyor means that conveys the conveyor pallet from the part-supplying station to the part-assembling station. In this assembly apparatus, the part-assembling station includes a part-supplying means that supplies some of the parts to an assembly robot for assembling the parts, and the assembly robot receives the some of the parts from the part-supplying means during a period for which the conveyor means conveys the conveyor pallet.
Since the above assembly apparatus according to the fourth embodiment of the present invention in which an operation using an assembly robot and a manual operation are combined is provided with a part-supplying means that supplies some of the parts other than those conveyed via the conveyor pallet within a range of a hand of the assembly robot, and configured to allow the assembly robot to receive the parts from the part-supplying means during the time period for which the conveyor means conveys the conveyor pallet to replace the same with the next conveyor pallet, so that the assembly robot may continue operating even during conveyance of the conveyor pallet. As a result, when the conveyor pallet stops at a work area in front of the assembly robot, the assembly robot has already held at least one part, and thus may immediately start assembling the part without performing a part-pick-up operation. Accordingly, the assembly apparatus in this embodiment of the present invention may contribute to a continuously maintained high serviceability ratio of the assembly robot, restricted investment in equipment, increased production efficiency by using the assembly robot, and enabled bulk production.
Moreover, according to a fifth embodiment of the present invention, there is provided an abnormal condition handling process in an assembly apparatus. The assembly apparatus includes a part-supplying station in which parts are supplied to a predetermined conveyor pallet through a manual operation, a part-assembling station in which the parts in the conveyor pallet are assembled through an operation using an assembly robot, and a conveyor means that conveys the conveyor pallet from the part-supplying station to the part-assembling station. In this embodiment, when an abnormal condition in assembling the parts by the assembly robot takes place in an assembly step, the assembly apparatus is suspended, and assembly of the parts is restarted from the assembly step at which the abnormal condition has taken place.
In the assembly apparatus as above in which an operation using an assembly robot and a manual operation are combined, when the assembly robot fails to hold a part or fails to assemble a part, first, the assembly apparatus is suspended, and then the assembly robot is allowed to start with the failed step of the assembly operation again, so that the yields of the product may be increased. Further, in this embodiment, the assembly robot performs all the steps of the assembly operation, and thus the quality of the product may also be kept at high levels.
It is understood that the failed part is not necessarily reassembled immediately when the abnormal condition is encountered. Depending upon circumstances of the abnormal condition in assembly, for example, an abnormal condition that has occurred in one assembly step would cause a part that has once been mounted normally to come off; thereby the steps upstream of the failed step would become necessitated reassembling in some instances. In such instances, the assembly operation of the pertinent work is temporarily suspended, and later put into an upstream defective assembly step to be carried out again so that the work may be reassembled, in that the work could not be inserted in the failed assembly step.
Other objects and further features of the present invention will become readily apparent from the following description of preferred embodiments with reference to accompanying drawings.